Voice over Data Networks for Managers BK7780532$49.99

Voice over Data Networks for Managers explains how and why companies converting their telephone systems to use voice over data systems. Learn how your company can reduce communication costs 40% to 70%, keep using your existing telephone systems, and increase revenue from new communication applications.

Sample Diagrams

There are 124 explanatory diagrams in this book

Data and Voice Cost Comparison

This table shows some sample comparisons between traditional charges for voice communication compared to the charges for sending data. This table shows that the average cost per minute for traditional telephone service (called switched voice) is approximately 4 cents per minute. If this service were to remain connected for 24 hours per day and 30 days in a month, this results in a monthly fee of $1,728. A 56 kbps switched connection at 0.2 cents per minute results in a monthly charge of $90. The approximate cost for fixed connections is $50 per month for 56 kbps, $500 per month for 1.5 Mbps (DS1), and $50,000 per month for 45 Mbps connections (DS3). If you adjust the monthly fee for a 64 kbps voice data rate (64 kbps/data rate divided by 30 days x 24 hours x 60 minutes), the average cost of data connection that is used for voice is 4 cents for switched voice, 0.22 cents for switched data, 0.13 cents for fixed 56 kbps, 0.05 cents for fixed 1.5 Mbps, and 0.016 cents per minute for 45 Mbps.

Basic Voice and Data Network Operation

This figure shows the basic network parts of VoIP networks and how they may be interconnected through private or public (e.g. Internet) data networks and some of the common servers that are used to manage the connections. In this example, an iPBX telephone at x102 dials a public telephone in Paris through the company's LAN system. When the PBX telephone is was first connected to the data network, it registered with the access server. The access server provides the IP telephone with access to the data network (such as the Internet) by assigning it an Internet address. When the user dials the telephone number for the phone in Paris, the IP telephone sends a call request message to the call server. The call server reviews its lists of gatekeepers (other servers) and determines the best choice for connecting the call. The call server then contacts the gatekeeper through the wide area network (WAN) connection and negotiates for a connection (bandwidth and features). A policy server has been programmed to give priority access voice communications on the WAN network connection to help ensure the call quality is acceptable. The gatekeeper then commands it's gateway to alert (ring) the telephone in Paris. If the recipient in Paris answers the phone, the call can be connected from extension 102, through the LAN, through the WAN, through the gateway, through the telephone network in Paris, to the telephone in Paris.

Backup Power for IP Telephony Systems

This figure shows how a backup power supply may be connected to the data communication equipment and the access devices to ensure telephone operation continues in the event of a power failure. When a power failure occurs, the uninterruptible power supply (UPS) supplies power to the DSU/CSU modem, router, call server, and inline power patch panel. The inline power patch panel provides power to the IP telephones that are connected to the data network.

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